won't power on: power supply or motherboard?

Discussion in 'Computer Support' started by that one, Apr 19, 2005.

  1. that one

    that one Guest

    Hello,
    we had an electrical spike at work today that blew out a hub/switch. My
    computer was off at the time, but still plugged into the battery which was
    plugged into the wall. After the surge, nothing happened when I pushed the
    On button on my pc--no fans started, nothing. I removed all unnecessary
    peripherals and tried again, tried different power cord, different outlet,
    all with same result. When the power cord is plugged in there's a small
    light on the motherboard that lights up. After I unplug, that light turns
    off after about 30 seconds. Unfortunately, we don't have any spare P4 power
    supplies laying around. So I'd like to hear what you think: is this a power
    supply failure or a motherboard failure, or is there enough information to
    tell? Thank you for your feedback.

    Oh, It's a p4 2.4Ghz Dell running XP Pro
     
    that one, Apr 19, 2005
    #1
    1. Advertising

  2. that one

    John Guest

    "that one" <none> wrote in message
    news:...
    > Hello,
    > we had an electrical spike at work today that blew out a hub/switch. My
    > computer was off at the time, but still plugged into the battery which was
    > plugged into the wall. After the surge, nothing happened when I pushed
    > the On button on my pc--no fans started, nothing. I removed all
    > unnecessary peripherals and tried again, tried different power cord,
    > different outlet, all with same result. When the power cord is plugged in
    > there's a small light on the motherboard that lights up. After I unplug,
    > that light turns off after about 30 seconds. Unfortunately, we don't have
    > any spare P4 power supplies laying around. So I'd like to hear what you
    > think: is this a power supply failure or a motherboard failure, or is
    > there enough information to tell? Thank you for your feedback.
    >
    > Oh, It's a p4 2.4Ghz Dell running XP Pro
    >Try finding the jumper for resetting the bios it may work


    John
     
    John, Apr 19, 2005
    #2
    1. Advertising

  3. that one wrote:
    > Hello,
    > we had an electrical spike at work today that blew out a hub/switch. My
    > computer was off at the time, but still plugged into the battery which was
    > plugged into the wall. After the surge, nothing happened when I pushed the
    > On button on my pc--no fans started, nothing. I removed all unnecessary
    > peripherals and tried again, tried different power cord, different outlet,
    > all with same result. When the power cord is plugged in there's a small
    > light on the motherboard that lights up. After I unplug, that light turns
    > off after about 30 seconds. Unfortunately, we don't have any spare P4 power
    > supplies laying around. So I'd like to hear what you think: is this a power
    > supply failure or a motherboard failure, or is there enough information to
    > tell? Thank you for your feedback.
    >
    > Oh, It's a p4 2.4Ghz Dell running XP Pro


    You can check the power supply with a voltmeter to see if that tells you
    anything, but swapping out parts is the only way to tell for sure. It
    may still be something else. You didn't mention which peripherals you
    took out but it could be a stick of RAM or the CPU or the video card,
    etc. If you want to do the voltmeter check, take one of the power plugs
    like the one that goes to a hard drive or CDROM and check the ground
    (black) and the red, it should be +5 volts DC. The black ground and the
    yellow should be 12VDC. But if there's a component shorted out in the
    system, the power supply may still be good but protecting itself by not
    powering up while there's a short.
     
    =?ISO-8859-1?Q?R=F4g=EAr?=, Apr 19, 2005
    #3
  4. that one

    Guest

    On Mon, 18 Apr 2005 20:37:21 -0500, "that one" <none> wrote:

    |>Hello,
    |>we had an electrical spike at work today that blew out a hub/switch. My
    |>computer was off at the time, but still plugged into the battery which was
    |>plugged into the wall. After the surge, nothing happened when I pushed the
    |>On button on my pc--no fans started, nothing. I removed all unnecessary
    |>peripherals and tried again, tried different power cord, different outlet,
    |>all with same result. When the power cord is plugged in there's a small
    |>light on the motherboard that lights up. After I unplug, that light turns
    |>off after about 30 seconds. Unfortunately, we don't have any spare P4 power
    |>supplies laying around. So I'd like to hear what you think: is this a power
    |>supply failure or a motherboard failure, or is there enough information to
    |>tell? Thank you for your feedback.
    |>
    |>Oh, It's a p4 2.4Ghz Dell running XP Pro
    |>

    (ATX)
    Unplug the power supply from the mother board.

    Power the supply, short the Green wire to any Black - If the power
    supply is good it will power on. (drives will start-up)

    If it doesn't power on, I'd suspect the mother board, or the fuse
    inside of the power supply.

    --
    www.Fark.com
     
    , Apr 19, 2005
    #4
  5. that one

    Guest

    On Mon, 18 Apr 2005 20:37:21 -0500, "that one" <none> wrote:

    (woops resent)

    |>Hello,
    |>we had an electrical spike at work today that blew out a hub/switch. My
    |>computer was off at the time, but still plugged into the battery which was
    |>plugged into the wall. After the surge, nothing happened when I pushed the
    |>On button on my pc--no fans started, nothing. I removed all unnecessary
    |>peripherals and tried again, tried different power cord, different outlet,
    |>all with same result. When the power cord is plugged in there's a small
    |>light on the motherboard that lights up. After I unplug, that light turns
    |>off after about 30 seconds. Unfortunately, we don't have any spare P4 power
    |>supplies laying around. So I'd like to hear what you think: is this a power
    |>supply failure or a motherboard failure, or is there enough information to
    |>tell? Thank you for your feedback.
    |>
    |>Oh, It's a p4 2.4Ghz Dell running XP Pro
    |>

    (ATX)
    Unplug the power supply from the mother board.

    Power the supply, short the Green wire to any Black - If the power
    supply is good it will power on. (drives will start-up)

    At which point I'd suspect the mother board, or the fuse inside of
    the power supply.

    If it doesn't power on, pry a bad power supply.

    --
    www.Fark.com
     
    , Apr 19, 2005
    #5
  6. that one

    EricP Guest

    On Mon, 18 Apr 2005 20:37:21 -0500, "that one" <none> babbled like a
    waterfall and said:

    >Hello,
    >we had an electrical spike at work today that blew out a hub/switch. My
    >computer was off at the time, but still plugged into the battery which was
    >plugged into the wall. After the surge, nothing happened when I pushed the
    >On button on my pc--no fans started, nothing. I removed all unnecessary
    >peripherals and tried again, tried different power cord, different outlet,
    >all with same result. When the power cord is plugged in there's a small
    >light on the motherboard that lights up. After I unplug, that light turns
    >off after about 30 seconds. Unfortunately, we don't have any spare P4 power
    >supplies laying around. So I'd like to hear what you think: is this a power
    >supply failure or a motherboard failure, or is there enough information to
    >tell? Thank you for your feedback.
    >
    >Oh, It's a p4 2.4Ghz Dell running XP Pro
    >

    Look on the back of the machine, by the plugs, there should be
    diagnostic lights. The handbook should tell you what they mean.
     
    EricP, Apr 19, 2005
    #6
  7. that one

    w_tom Guest

    Don't even disconnect anything inside the machine. That
    takes too long and sometimes leads to misleading results.

    Start first with a protection circuit located in part of the
    power supply 'system' (the power supply is only one part of
    the power supply system). IOW remove power cord from machine,
    count to two, and reconnect power cord. This will reset the
    protection system. (However I believe you have already done
    that).

    The next step is that meter as noted by Rôgêr. Meters are
    by far the best, fastest, and accurate way to locate the
    defective part. Far more accurate than swapping parts.

    First measurement is a DC volt measurement from purple wire
    to black wire. IOW put meter selector on DC voltages, then
    touch leads to those two wires. Its that complex.

    That purple wire (called +5VSB) must always have power if
    the power cord is properly connected to wall receptacle. Just
    another reason why you don't want to disconnect anything
    (never remove anything from a computer when the purple wire
    has voltage).

    Then measure green to black wires. When ordered by the
    'power supply controller' to be off, the green wire measures
    more than 2.4 volts. When the power switch is pressed, then
    power supply controller (which is not inside the power supply)
    drops green wire voltage to less than 0.8. IOW without doing
    any disconnecting, you know have done even more than the
    'green wire to black wire' jumper (that does not work on some
    supplies).

    If a pressed power switch does cause the green wire to drop
    to less than 0.8 volts, then critical voltages should appear
    on red, orange, and yellow wires. Confirm one of each colored
    wire using the meter.

    Don't forget to record those numbers. Those numbers mean
    nothing to you. But numbers tell your better informed
    assistants much more about your system. What does the red,
    orange, and yellow wires do in the first two seconds after
    power switch is pressed? Again, a critically important fact
    that can identify which component in a power supply 'system'
    is defective.

    Notice a UPS did nothing to protect the computer. Just
    another example of what a battery UPS does. It is not for
    hardware protection. That UPS is only to protect computer
    data.

    Get the numbers and report back.

    that one wrote:
    > Hello,
    > we had an electrical spike at work today that blew out a hub/switch. My
    > computer was off at the time, but still plugged into the battery which was
    > plugged into the wall. After the surge, nothing happened when I pushed the
    > On button on my pc--no fans started, nothing. I removed all unnecessary
    > peripherals and tried again, tried different power cord, different outlet,
    > all with same result. When the power cord is plugged in there's a small
    > light on the motherboard that lights up. After I unplug, that light turns
    > off after about 30 seconds. Unfortunately, we don't have any spare P4 power
    > supplies laying around. So I'd like to hear what you think: is this a power
    > supply failure or a motherboard failure, or is there enough information to
    > tell? Thank you for your feedback.
    >
    > Oh, It's a p4 2.4Ghz Dell running XP Pro
     
    w_tom, Apr 19, 2005
    #7
  8. that one

    Tina Guest

    "that one" <none> wrote in message
    news:...
    > Hello,
    > we had an electrical spike at work today that blew out a hub/switch.
    > My computer was off at the time, but still plugged into the battery
    > which was plugged into the wall. After the surge, nothing happened
    > when I pushed the On button on my pc--no fans started, nothing. I
    > removed all unnecessary peripherals and tried again, tried different
    > power cord, different outlet, all with same result. When the power
    > cord is plugged in there's a small light on the motherboard that
    > lights up. After I unplug, that light turns off after about 30
    > seconds. Unfortunately, we don't have any spare P4 power supplies
    > laying around. So I'd like to hear what you think: is this a power
    > supply failure or a motherboard failure, or is there enough
    > information to tell? Thank you for your feedback.
    >
    > Oh, It's a p4 2.4Ghz Dell running XP Pro
    >



    If you buy another PSU, you might run into difficulties since Dell does
    not use a standard ATX PSU connectors.
    http://www.endpcnoise.com/cgi-bin/e/dellconverter.html

    --
    Tina
     
    Tina, Apr 19, 2005
    #8
  9. John wrote:

    > "that one" <none> wrote in message
    > news:...
    >> Hello,
    >> we had an electrical spike at work today that blew out a hub/switch. My
    >> computer was off at the time, but still plugged into the battery which was
    >> plugged into the wall. After the surge, nothing happened when I pushed
    >> the On button on my pc--no fans started, nothing. I removed all
    >> unnecessary peripherals and tried again, tried different power cord,
    >> different outlet, all with same result. When the power cord is plugged in
    >> there's a small light on the motherboard that lights up. After I unplug,
    >> that light turns off after about 30 seconds. Unfortunately, we don't have
    >> any spare P4 power supplies laying around. So I'd like to hear what you
    >> think: is this a power supply failure or a motherboard failure, or is
    >> there enough information to tell? Thank you for your feedback.


    >> Oh, It's a p4 2.4Ghz Dell running XP Pro
    >>Try finding the jumper for resetting the bios it may work


    Why are you putting a ">" quote indicator in front of your reply, thus
    making it look like part of the message you're replying *to*?

    http://www.dickalba.demon.co.uk/usenet/guide/index.html

    --
    Blinky Linux Registered User 297263
    Killing all Usenet posts from Google Groups
    Info: http://blinkynet.net/comp/uip5.html
     
    Blinky the Shark, Apr 21, 2005
    #9
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. John

    Motherboard / Power SUpply Issue

    John, Jul 24, 2003, in forum: Computer Support
    Replies:
    4
    Views:
    3,364
    Jeffrey Edwards
    Jul 24, 2003
  2. Chris

    Power Supply or Motherboard Knackered.

    Chris, Dec 20, 2003, in forum: Computer Support
    Replies:
    10
    Views:
    781
    Ghostmaster
    Dec 20, 2003
  3. Gregg Fowler

    PC Died: Motherboard or Power Supply? Help!

    Gregg Fowler, Feb 4, 2004, in forum: Computer Support
    Replies:
    10
    Views:
    2,896
    Champagne Charlie
    Feb 5, 2004
  4. Q

    Dead Power Supply and Motherboard...

    Q, Jan 28, 2005, in forum: Computer Support
    Replies:
    5
    Views:
    2,594
  5. nick
    Replies:
    0
    Views:
    1,442
Loading...

Share This Page